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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network10.167.248.0/22
Usable hosts1,022
Subnet mask255.255.252.0
Addresses1,024
Network address
10.167.248.0
Broadcast address
10.167.251.255
First usable
10.167.248.1
Last usable
10.167.251.254
Usable hosts
1,022 (1,024 less the network and broadcast addresses)
Subnet mask
255.255.252.0
Wildcard mask
0.0.3.255 (Cisco ACLs, OSPF)
Prefix length
/22
Type
Private (RFC 1918) 10.0.0.0/8
Office and home networks; not routed on the internet
Old class
A (default /8)
As numbers
Hex 0AA7F800 · Integer 178780160 to 178781183
Reverse DNS zones
248.167.10.in-addr.arpa
249.167.10.in-addr.arpa
250.167.10.in-addr.arpa
251.167.10.in-addr.arpa
/22 is not on a 8-bit boundary, so it takes 4 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00001010.10100111.11111000.0000000010.167.248.0
Subnet mask11111111.11111111.11111100.00000000255.255.252.0
Network00001010.10100111.11111000.0000000010.167.248.0
Broadcast00001010.10100111.11111011.1111111110.167.251.255
Split into smaller subnets/28
/23 (2)/24 (4)/25 (8)/26 (16)/27 (32)/28 (64)/29 (128)/30 (256)/31 (512)/32 (1,024)

10.167.248.0/22 makes 64 subnets of /28.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
110.167.248.0/2810.167.248.1 to 10.167.248.1410.167.248.1514
210.167.248.16/2810.167.248.17 to 10.167.248.3010.167.248.3114
310.167.248.32/2810.167.248.33 to 10.167.248.4610.167.248.4714
410.167.248.48/2810.167.248.49 to 10.167.248.6210.167.248.6314
510.167.248.64/2810.167.248.65 to 10.167.248.7810.167.248.7914
610.167.248.80/2810.167.248.81 to 10.167.248.9410.167.248.9514
710.167.248.96/2810.167.248.97 to 10.167.248.11010.167.248.11114
810.167.248.112/2810.167.248.113 to 10.167.248.12610.167.248.12714
910.167.248.128/2810.167.248.129 to 10.167.248.14210.167.248.14314
1010.167.248.144/2810.167.248.145 to 10.167.248.15810.167.248.15914
1110.167.248.160/2810.167.248.161 to 10.167.248.17410.167.248.17514
1210.167.248.176/2810.167.248.177 to 10.167.248.19010.167.248.19114
1310.167.248.192/2810.167.248.193 to 10.167.248.20610.167.248.20714
1410.167.248.208/2810.167.248.209 to 10.167.248.22210.167.248.22314
1510.167.248.224/2810.167.248.225 to 10.167.248.23810.167.248.23914
1610.167.248.240/2810.167.248.241 to 10.167.248.25410.167.248.25514
1710.167.249.0/2810.167.249.1 to 10.167.249.1410.167.249.1514
1810.167.249.16/2810.167.249.17 to 10.167.249.3010.167.249.3114
1910.167.249.32/2810.167.249.33 to 10.167.249.4610.167.249.4714
2010.167.249.48/2810.167.249.49 to 10.167.249.6210.167.249.6314
2110.167.249.64/2810.167.249.65 to 10.167.249.7810.167.249.7914
2210.167.249.80/2810.167.249.81 to 10.167.249.9410.167.249.9514
2310.167.249.96/2810.167.249.97 to 10.167.249.11010.167.249.11114
2410.167.249.112/2810.167.249.113 to 10.167.249.12610.167.249.12714
2510.167.249.128/2810.167.249.129 to 10.167.249.14210.167.249.14314
2610.167.249.144/2810.167.249.145 to 10.167.249.15810.167.249.15914
2710.167.249.160/2810.167.249.161 to 10.167.249.17410.167.249.17514
2810.167.249.176/2810.167.249.177 to 10.167.249.19010.167.249.19114
2910.167.249.192/2810.167.249.193 to 10.167.249.20610.167.249.20714
3010.167.249.208/2810.167.249.209 to 10.167.249.22210.167.249.22314
3110.167.249.224/2810.167.249.225 to 10.167.249.23810.167.249.23914
3210.167.249.240/2810.167.249.241 to 10.167.249.25410.167.249.25514
3310.167.250.0/2810.167.250.1 to 10.167.250.1410.167.250.1514
3410.167.250.16/2810.167.250.17 to 10.167.250.3010.167.250.3114
3510.167.250.32/2810.167.250.33 to 10.167.250.4610.167.250.4714
3610.167.250.48/2810.167.250.49 to 10.167.250.6210.167.250.6314
3710.167.250.64/2810.167.250.65 to 10.167.250.7810.167.250.7914
3810.167.250.80/2810.167.250.81 to 10.167.250.9410.167.250.9514
3910.167.250.96/2810.167.250.97 to 10.167.250.11010.167.250.11114
4010.167.250.112/2810.167.250.113 to 10.167.250.12610.167.250.12714
4110.167.250.128/2810.167.250.129 to 10.167.250.14210.167.250.14314
4210.167.250.144/2810.167.250.145 to 10.167.250.15810.167.250.15914
4310.167.250.160/2810.167.250.161 to 10.167.250.17410.167.250.17514
4410.167.250.176/2810.167.250.177 to 10.167.250.19010.167.250.19114
4510.167.250.192/2810.167.250.193 to 10.167.250.20610.167.250.20714
4610.167.250.208/2810.167.250.209 to 10.167.250.22210.167.250.22314
4710.167.250.224/2810.167.250.225 to 10.167.250.23810.167.250.23914
4810.167.250.240/2810.167.250.241 to 10.167.250.25410.167.250.25514
4910.167.251.0/2810.167.251.1 to 10.167.251.1410.167.251.1514
5010.167.251.16/2810.167.251.17 to 10.167.251.3010.167.251.3114
5110.167.251.32/2810.167.251.33 to 10.167.251.4610.167.251.4714
5210.167.251.48/2810.167.251.49 to 10.167.251.6210.167.251.6314
5310.167.251.64/2810.167.251.65 to 10.167.251.7810.167.251.7914
5410.167.251.80/2810.167.251.81 to 10.167.251.9410.167.251.9514
5510.167.251.96/2810.167.251.97 to 10.167.251.11010.167.251.11114
5610.167.251.112/2810.167.251.113 to 10.167.251.12610.167.251.12714
5710.167.251.128/2810.167.251.129 to 10.167.251.14210.167.251.14314
5810.167.251.144/2810.167.251.145 to 10.167.251.15810.167.251.15914
5910.167.251.160/2810.167.251.161 to 10.167.251.17410.167.251.17514
6010.167.251.176/2810.167.251.177 to 10.167.251.19010.167.251.19114
6110.167.251.192/2810.167.251.193 to 10.167.251.20610.167.251.20714
6210.167.251.208/2810.167.251.209 to 10.167.251.22210.167.251.22314
6310.167.251.224/2810.167.251.225 to 10.167.251.23810.167.251.23914
6410.167.251.240/2810.167.251.241 to 10.167.251.25410.167.251.25514

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.